Control apparatus for internal-combustion engines



Dec. 9, '1952 L. LEE, IL 2,620,783

CONTROL APPARATUS FOR INTERNAL-OOMBUSTION ENGINES Filed March 16, 1946 5 sheets-Sheet 1 BY f"\ w r i Ar Raad:

Dec. 9, L. LEE,I[ CONTROL APPARATUS FOR INTERNAL-COMBUSTION ENGINES Filed March 16, 1946 3 Sheets-Sheet 2 1N VEN TOR.

[l5/@9727 LEBE Hanni Dec. 9, 1952 l.. LEE, n 2,620,783

CONTROL. APPARATUS FOR INTERNAL-COMBUSTION ENGINES Filed MaICh l5, 1946 5 Sheets-Sheet 5 suPERcHAR'sER GEAR RATIO SELECTOR IN V EN TOR.

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Patented Dec. 9, 1952 CONTROL APPARATUS FOR INTERNAL- COMBUSTION ENGINES Leighton Lee, II, Rocky Hill, Conn., assgnor, by mesne assignments, to Niles-Bement-Pond Company, West Hartford, Conn., a corporation of New Jersey Application March 16, 1946, Serial No. 654,978

(Cl. 12S-103) 17 Claims. 1

The present invention relates to control apparatus for internal combustion engines, and particularly to apparatus for controlling the flow of combustion air to such engines.

Internal combustion engines are commonly controlled by throttling the supply of incoming combustion air. The throttle mechanism is customarily operated by a manual control. It has also been proposed to provide automatic controls for the throttles which would maintain a constant rate of air flow, which rate may be manually selected. Such automatic systems have the disadvantage that they generally lag somewhat behind a change in the selected rate of air flow. Also, some means must be provided for operating the throttle manually in case of failure of the automatic system, Such an arrangement results in complication of the throttle control. A manually controlled throttle does not have those disadvantages, but it does have the disadvantage that the rate of air flow may Vary from any of several different causes, such as varying engine speed, quite independently of the throttle position.

It is an object of the present invention to provide an improved system for controlling the throttle of an internal combustion engine.

It is a further object to provide such a system which includes the advantages of the manually and automatically controlled systems without the disadvantages of either.

In particular, one object is to provide an automatic throttle control system which is very sensitive to movements of its manual controller, but which will not hunt.

Another object of the present invention is to provide an air flow control system for an internal combustion engine which includes two separately movable throttle blades, manual means for operating one blade, automatic means for operating the other blade in response to the rate of air flow, and means depending upon the position of the manual blade to control the rate of air flow to be maintained by positioning of the automatically operated blade.

A further object of the present invention is to provide an improved means for coordinating the throttle of an internal combustion engine with a device for regulating the speed of a supercharger supplying compressed air to the engine.

A further object is to provide such improved coordinating means for controlling a turbine driven supercharger.

A further object is to provide such improved coordinating means for controlling a supercharger which is directly driven by vthe engine.

Other objects and advantages of my invention will become apparent from a consideration of the appended specification, claims and drawings, in which Figure 1 illustrates, somewhat diagrammatically, a carburetor for an internal combustion engine, including a throttle structure to which my invention may be applied.

Figure 2 illustrates, somewhat diagrammatically, throttle control apparatus for use with the carburetor of Figure 1 and apparatus for controlling the waste gate of a turbine driven sup-ercharger, and

Figure 3 illustrates, somewhat diagrammatically, throttle controlling apparatus for the carburetor of Figure 1, together with apparatus for operating the gear ratio selector of a direct driven supercharger.

Referring to Figure 1, there is shown an air induction conduit ID, thru which air lows from an entrance I2, past a venturi It, a pair -of throttle blades, I6 and I8, and a fuel-discharge nozzle 20 to a discharge outlet 22.

Fuel enters the carburetor from a pump thru a conduit 24, and ows thru a fuel regulator 26, a conduit 28, a mixture control 30, a jet system 32, an idle valve mechanism 3H, a conduit 36, a pressure regulator 38 and a conduit 4 8 to the fuel discharge nozzle 2E). y

The air owing thru a venturi vIt sets up a differential pressure which varies with the velocity of flow. This diierential pressure produces a ow of air thru a secondary air conduit. The entrance to this secondary conduit is formed by a plurality of impact tubes 42, whose open ends project into the entrance I2 so as to receive the impact of the entering air. From these impact tubes 42, the air flows thru a conduit 4d, a chamber in a fuel meter 48, a fixed restriction 5S, a chamber 52 in the fuel meter Q3, a conduit 5, past a valve 56 into a chamber 58 and thence thru a conduit to the throat of venturi Ill.

The valve 56 is operated by a flexible bellows 62 mounted in the chamber 48. The bellows e2 operates the valve 55 in accordance with variations in the pressure of the air iiowing thru the main induction conduit. This bellowsA maybe lled with a temperature responsive iiuidso that the valve 55 also responds to the temperature in the main air conduit. The function of bellows 62 and valve 56 is to correct the air pressure differential appearing across restriction 5D for variations in the air density, so that that air pressure differential is a measure of themass of air owing per unit time thru the main conduit Iii. The action of this density compensating mechanism is more completely described in the copending application of Milton E. Chandler, Serial No. 490,281, led June l0, 1943. This air pressure differential, which is a measure of the mass of air flowing per unit time to the engine acts downwardly on a diaphragm 64 which separates the chambers 46 and 52. The diaphragm B4 is attached at its center to the stem 65 of a pilot valve 68.

The fuel regulator 26 includes a pair of eX- pansible chambers 'l0 and 'l2 separated by a flexible diaphragm 14. A valve 'f6 is attached to the center of the diaphragm '14. A spring T8 biases the valve 'I6 toward open position. The valve 16 acts as an inlet valve for chamber '|2, which is connected to the fuel conduit 28. The chambers and 'l2 are connected thru a fixed restriction 80.

The mixture control 36, includes a disc valve 82 mounted on a manually rotatable shaft 84. When the valve 82 is in the position shown in full lines on the drawing, hereinafter termed its lean position, fuel may flow to the jet system 32 only thru a conduit 86. When the disc valve 82 is moved to the dotted line position in the drawing, hereinafter termed its rich position, then fuel may flow to the jet system thru a conduit 88 also. The valve 82 may also be moved to a position where it cuts off the flow thru both cOnduits 86 and 88, which is termed its cut-off position.

Fuel entering the jet system 32 from conduit 86 passes either thru a fixed restriction S0 or restriction 92 controlled by a valve 94 which is biased closed by a spring 96. Fuel entering the jet system thru conduit 88 flows thru a fixed restriction 98. Fuel passing thru restrictions 92 and 88 also passes thru another xed restriction |00. The valve 94 is provided for the purpose of enriching the fuel mixture under conditions of high power output. The restriction |00 is to limit the maximum flow obtainable thru restrictions 92 and 98.

The idle valve mechanism 34 includes a valve |02 Operated by a shaft |04, which is connected thru an arm |06 and a link |08 to an arm ||0 on the shaft |2 of throttle blade I8. The construction is such that the valve |02 is open whenever the throttle blade |8 is out of the idle range. As the throttle blade |8 nears its closed position, the valve |02 is moved toward its closed position.

The pressure regulator 38 includes a flexible diaphragm ||4 separating a pair of expansible chambers ||6 and IIB. A valve |20 is attached to the center of diaphragm |4 and is biased toward closed position by a spring |22. The chamber ||6 receives fuel from the conduit 36. The valve regulates the flow of fuel from chamber ||8 into conduit 40. The chamber ||8 is vented to atmosphere thru a conduit |24 which connects to conduit 44.

The pressure regulator 38 acts to maintain a ,substantially constant pressure in the fuel line on the downstream side of the jet system 32. The jet system 32 acts as a metering restriction in the fuel line whose effective area may be varied by the mixture control or by the operation of valve 94. The fuel regulator 26 controls the pressure in the fuel line on the upstream side of the jet system so as to vary that pressure substantially in accordance with the rate of air flow and hence to maintain the fuel flow proportional to the air flow, as hereinafter described.

A portion of the fuel entering chamber f2 of the fuel regulator 26 passes thru restriction 86 and thence thru a conduit |25 |20 a Chamber |28 in the fuel meter 48. Fuel flows from a chamber |28 thru the pilot valve 68 to a drain conduit |30 which is shown as being connected to the main air induction conduit. The drain conduit |30 may alternatively be connected back to the fuel tank or to any other suitable place for the disposal of the fuel passing thru it. The chamber |28 is separated from chamber 52 by a diaphragm |32. The fuel meter 48 also includes a chamber |34 separated from chamber 46 by a diaphragm |36. Chamber |34 is connected thru a conduit |40 to the conduit 36 on the downstream side of the jet System. The three diaphragms |35, 64 and |32 are all cOnnected to the stem 86 of pilot valve 68. A spring |38 biases the valve 68 toward closed position. The pressure in chamber |28, which acts upwardly on the valve 68, differs from the pressure in chamber 'l2 only by an amount determined by the force of spring 18, which is substantially constant. The pressure in chamber 28 is therefore a measure of the fuel pressure on the upstream side of the jet system. The pressure in chamber |34 is the same as the fuel pressure 0n the downstream side of the jet system. The difference between these two pressures is a measure of the rate of fuel flow, and this difference acts upwardly on the valve 68 and is balanced by the air differential pressure acting downwardly on diaphragm 64.

When the air pressure differential acting downwardly on valve 68 is balanced by the fuel pressure differential acting upwardly, then the fuelair ratio is maintained constant at a value determined by the cross-sectional area of the jet system open to the flow of fuel, which determines the rate of fuel flow produced by a given fuel pressure differential across the jet system.

If the air pressure differential increases and thereby exceeds the fuel pressure differential acting upwardly on valve 68, then the valve moves downwardly toward closed position. rlhis causes an increase in pressure in chamber I 28. The downward movement of valve 68 continues until the fuel pressure differentia] acting upwardly balances the air pressure differential. This increased pressure in chamber |28 is transmitted to chamber 'l0 of fuel regulator 26, where it causes an opening movement of valve 'f6 to increase the pressure in chamber 'l2 by a corresponding amount. This increases the fuel pressure differential across the jet system, and thereby increases the fuel flow until it balances the air flow.

From the foregoing, it may be seen that the pressure in chamber |28 is a measure of the rate of flow of air to the engine. This pressure is communicated thru conduit |26 and a conduit |42 to a throttle controlling mechanism shown more completely in Figure 2.

Under low air flow conditions, such as occur when an engine is idling, a Venturi meter such as that shown at |4 does not provide an accurate measure of air flow, inasmuch as its throat area must be designed so that it measures accurately at much higher ows. In other words, the range of air flows encountered is much greater than a single fixed throat Venturi meter can measure accurately. It is therefore desirable to provide means for controlling the fuel flow independently of the pressure differential existing at the venturi under low air flow conditions. It is also desirable to increase the fuel-air ratio under idling conditions to ensure smooth engine operation.

Such idle control means are provided in the carburetor of Figure 1 by the spring |38 in the fuel meter 48, the spring 18 in the fuel regulator aezofzss 28, and the idle valve |02. The springs |38 and 18 cooperate to establish a, minimum value for the fuel pressure differential across the jet system. Even when the pressure differential set up by the air venturi |4 is zero, the valve 88 is biased closed by the spring |38 so as to cause opening of valve 18 until the fuel pressure differential acting upwardly on valve 88 balances the spring |38. At such times, the throttles are near closed position, and the opening thru valve |02, being then smaller than the area of jet 80, is the effective metering restriction. By properly designing springs |38 and 18 and the contour of valve |02, the fuel-air ratio under idle conditions may be controlled as desired.

Figure 2 Referring to Figure 2, it may be seen that the throttle blade |8 is positioned by a manually operated link |44, which is pivotally connected to one end of the arm H0. The other end of arm ||0 is provided with a slot |48. A rod |48 carries a pin |50 which rides in the slot |48. The other end of rod |48 extends into a valve operating mechanism |52. The mechanism |52 includes a diaphragm |54 separating a pair of expansible chambers |58 and |58. The conduit |42 (see Figure 1) communicates with chamber |58. The chamber |58 is vented to the atmosphere as indicated at |80. The rod |48 carries, within the chamber |58, a spring retainer |82. A compression spring |84 is held between the retainer |82 and the diaphragm |54. A spool valve |88 is attached to the opposite side of diaphragm |58. The valve |88 selectively controls the direction of flow of fluid from a supply conduit |88 thru a servo-motor to a drain conduit |12. The supply conduit |88 has a pair of branches |14 and |18. When the valve |88 is in the position shown in the drawing, the supply conduits |14 and |18 are blocked by lands |18 and |80, respectively, of the valve |88, and the drain conduit |12 is blocked by a land |82.

The servo-motor |10 includes a piston |84 which is slidable in a cylinder |88. A stop |88 limits the movement of piston |84 to the left. A rod |90 is connected to piston |84 and at its opposite end carries a pin |92 which moves in a slot |84 in a lever |98. The opposite end of lever |88 is connected to a link |88 which is in turn connected to an arm 288 on the shaft 202 of throttle blade I8.

A port 204 in the wall of cylinder |88 is connected thru a conduit 286 to another servo-motor 288. The servo-motor 208 includes a cylinder 2|8, and a piston 2|2 slidable therein. A spring 2|4 biases the piston 2|2 to the left against a stop 2|8. The space between the left face of piston 2|2 and the end of the cylinder 2|0 is connected thru a, conduit 2 8 having a restriction 220 therein to the drain conduit |12.

The piston 2|2 is attached to a rod 222 connected thru a link 224 to a waste gate 228. The waste gate 228 is a by-pass valve, which when open permits the exhaust gases from the engine to pass directly to the atmosphere without going thru an exhaust gas turbine 228 which drives a supercharger 280 for supplying air under pressure to the engine. The supercharger intake is shown at 232 and its discharge conduit at 234. The discharge conduit 234 leads directly into the air induction conduit |0.

Operation of Figure 2 The throttle blade |8 is manually controlled by means of link |44. As the blade |8 is moved toward open position, arm ||0 moves the rod |48 to the left, increasing the force of spring |84 acting to the left on valve |88. This moves valve |88 to the left, thereby allowing fluid to flow from supply conduit |88 thru conduit |14, past land |18, thru conduit 238 to the left end of cylinder |88. At the same time, the right end of cylinder |88 is connected thru conduit 238 and past valve |88 to the drain conduit |12. The difference in pressure acting on piston |84 moves it to the right, thereby rotating lever |98 clockwise and opening throttle blade I8. This opening movement of throttle blade I8 continues until the air now is increased suiciently to increase the pressure in chamber |58 (as described in connection with Figure 1) so as to balance the increased force of spring |84.

Thereafter the system tends to maintain an air flow determined by the setting of spring |84. If the air ow differs from the value which causes the pressure in chamber |58 to balance the force of that spring, then the throttle |8 is operated to vary the air flow to restore that balance. When the throttle |8 reaches its full opened position, the piston |84 uncovers the port 204, and fluid under pressure is then supplied to the chamber 2|3 in the servo-motor 208. This causes the piston 2|2 to move to the right thereby closing the Waste gate 228 and increasing the flow of exhaust gas thru the turbine 228. This increases the speed of the supercharger 230 and therefore the fiow of air to the engine. When the flow of air becomes suicient so that valve |88 is moved to the right so that the flow of fluid past valve |88 and piston |84 into chamber 2|3 just balances the discharge of iiuid from chamber 2|3 thru restriction 220, then the waste gate stops moving. If the air flow thereafter changes, then the waste gate position is corrected until the proper air ow is again maintained. If conditions change so that the proper air ow can be maintained without the use of the supercharger, the waste gate will completely open and the system will then control the throttle as above.

As previously explained, the spring |38 in fuel meter 48 (see Figure 1) establishes a minimum value for the fuel pressure diierential acting upwardly on valve 88. Since the pressure in chamber |34 is maintained substantially constant by the action of pressure regulator 38, it may be stated that the spring |38 establishes a minimum value for the pressure in chamber |28, which pressure is transmitted thru conduit |42 to chamber |58.

The spring |84 is preferably so designed that when the throttle blade I8 approaches closed position, the spring is not lstrong enough to overcome the minimum' pressure which may exist in chamber |28. Therefore, at such times valve |88 is moved to the right, causing operation of the throttle blade |8 to its completely closed position. Control of the rate of air flow to the engine is therefore accomplished, under idle conditions, exclusively by the use of the manually operable throttle blade I8.

Altho in the illustrated modications of my invention, I have used the pressure in the chamber |28, communicated thru conduit |42, as a measure of air ow for the purpose of controlling the throttles, it should be realized that other pressures or pressure differentials could be used to oppose spring |84, as long as such pressure or pressure differential is a measure of air ow. For example, either the air pressure differential acting on diaphragm 84 of Figure 1, or the fuel pres.-

sure differential across the jet system 32, could be applied directly to the diaphragm 154. Either of those two pressure differentials may be used as a measure of air flow.

Figure 3 There is shown in Figure 3 an arrangement wherein the throttle control mechanism is generally the same as that of Figure 2. Additional control mechanism is shown for a gear ratio selector for a direct driven supercharger. The control mechanism for this gear ratio selector is somewhat different from that employed for the waste gate in Figure 2. The parts of the throttle and control mechanism of Figure 3 have been given the same reference characters as the corresponding parts in Figure 2.

Referring to Figure 3, there is shown a gear rat-io selector 258 provided with a lever 252 movable between a low speed position and a high speed position. The end of lever 252 is slotted, as at 254 to receive a pin 256 on the end of a rod 258. The rod 258 is operated by a piston E88, which is biased to the left by a spring 262. A stop 284 limits the leftward movement of piston 283. The piston 288 moves in a cylinder 25a. A chamber 268 is formed between the left face of piston 288 and the end of cylinder 288. The chamber 288 is connected thru a conduit 218 to an accumulator bellows 212 located in a housing 214. A stop 218 is provided for limiting the expansion of bellows 212. 'Ihe chamber 288 is also connected thru a conduit 218 to a conduit 288 leading to a port 282 adjacent the land |18 of valve IEB. The conduit 218 also connects with a valve 28.4 leading to a drain conduit 286. Valve 284 is formed on a rod 285 connected to piston IM. Valve 281i is closed when throttle i6 is wide open or almost wide open, and is opened upon movement of throttle i6 outside of a narrow range of positions adjacent its wide open position.

Operation of Figure 3 The system of Figure 3 normally controls the throttle blade I6 to maintain the rate of air flow selected by the adjustment of the force of spring 164. If the throttle I8 reaches its wide open position and the air flow falls below the selected value, then the valve 166 continues to move to the left beyond the position at which it causes an opening movement of the throttle I5. Valve 284 is then closed. If this leftward movement of valve |66 continues, port 282 is opened to the high pressure fluid supply line |14. Fluid then passes thru conduits 288 and 218 to chamber 268. The spring rate of bellows 212 is chosen to be less than that of the spring 252, so that when the high pressure fluid reaches chamber 268 it first expands the bellows 212 against its stop 216, and thereafter causes movement of piston 260 to the right. Therefore the accumulator bellows 212 provides a time delay between the falling off of the air ow below its selected value and the shifting of the supercharger from low to high. The reason for this time delay will become apparent when it is considered that the shift of the supercharger from low speed to high speed provides a sudden increase in air flow, and of a considerable magnitude. If the increase is too great, it may be sufficient to cause the control mechanism to reverse and shift the supercharger back to low speed. A hunting condition might then be established, with the gear ratio selector shifting back and forth from low to high speed. By providing the time delay, it is insured that the demand for increased air flow is sufficient at the time of the shift to high speed so that the supercharger will remain at its high speed after the shift is made.

If, with the supercharger running at high speed the rate of air flow selected is reduced, or if the rate of air fiow becomes too great for that selected, then the valve |66 moves to the right, causing movement of the throttle l5 toward closed position. As this movement continues, a point is eventually reached where the valve 284 is opened. The chamber 268 is then drained thru conduit 218, valve 284 and conduit 285, the force to discharge fluid from chamber 288 being supplied by spring 282 and the tension of bellows 212. The supercharger gear ratio is then restored to its low speed condition. The throttle I6 is then positioned to restore the desired air flow under low supercharger speed conditions.

From the foregoing, it may be seen that in my improved throttle control system, a movement of the manually operable lever results in immediate movement of the throttle blade I8, regardless of any lag which may occur in the operation of the throttle blade l5. Furthermore, if the automatic mechanism controlling the throttle blade i6 fails for any reason, the operator still has partial control of the rate of air flow to the engine by means of the throttle blade I8.

Because of the rapid response of the manually operated throttle blade I8, it is possible to construct the control system for the automatically operated blade I8 so that its movements are highly damped. By such damping, hunting of the automatic control system may be prevented without loss of sensitivity or rapidity of response of the complete system including both manual and automatic blades.

The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention, in the use of such terms and expressions, of excluding any equivalents of the features shown and described or portions thereof, but recognize that various modifications are possible within the scope of the invention claimed.

I claim as my invention:

1. Control apparatus for an internal combustion engine, comprising a conduit for air flowing to said engine, a pair of throttle blades for controlling the flow of air thru said conduit, means for manually moving one of said throttle blades, motor means for simultaneously moving the other of said throttle blades, and means connected for concurrent movement with said one throttle blade for controlling said motor means to coordinate the simultaneous movements of said other throttle blade.

2. Control apparatus for an internal combustion engine, comprising a conduit for air flowing to said engine, a pair of throttle blades for controlling the flow of air thru said conduit, means for manually moving one of said throttle blades, motor means for moving the other of said throttle blades, a device for controlling said motor means, said device having a neutral position in which said motor means is stationary and being effective upon movement from said neutral position in either direction to cause operation of said motor means in a corresponding direction, means responsive to the rate of air now thru said conduit for moving said device in an air fiow decreasing direction, spring means opposing said air flow responsive means, and means associated with said one throttle blade for increasing the opposing force of said spring means as said one blade is moved toward open position.

3,'Control apparatus for an internal combustion engine, comprising a conduit for air owing to said engine, a pair'of throttle blades for controlling the now of air thru said conduit, means for manually moving one of said throttle blades, motor means for moving the other of said throttle blades, means responsive to the rate of air flow thru said conduit for controlling said motor means to maintain a substantially constant air flow, means for varying the setting of said air ow responsive means, and means associated with said one throttle blade for operating said setting Varying means in a flow increasing sense as said one bl-ade is moved toward open position.

4. Control apparatus for aninternal combustion engine, comprising a conduit for air flowing to said engine, a pair of throttle blades for controlling the ilow of air thru said conduit, means for manually moving one of said throttle blades, motor means for moving the other of said throttle blades, a device for controlling said motor means, said device having a neutral position in which said motor means is stationary and being effective upon movement from sai-d neutral position in either direction to cause operation of said motor means in al corresponding direction, means normally responsive to the rate of air ilovv thru said conduit for applying a force to said device in an air flow decreasing direction, means for establishing a minimum value for said force regardless of said air flow, spring means opposing said air oW responsive means, and means associated with said one throttle blade for increasing the opposing force of said spring means as said one blade is moved toward open position, and for decreasing the opposing force of said spring means as said one blade is moved toward closed position, said device, said last-named means and said minimum establishing means cooperating to cause movement of said other throttle blade to closed position whenever the force of said spring means becomes less than that established by said minimum establishing means.

5. Control apparatus for an internal co-mbustion engine having a throttle for controlling the flow of combustion air to said engine, a supercharger for supplying air under pressure to said engine, an exhaust gas turbine for driving said supercharger, and a waste gate for regulating the operation of said supercharger; said control apparatus comprising a first hydraulic servomotor for operating said throttle, including a cylinder and a piston reciprocable therein, means for selectively supplying iluid at high pressure to either end of said cylinder and connecting the opposite end of said cylinder to a source of lower pressure to cause translation of said piston selectively in `opposite directions, a second hydraulic servomotor for operating said waste gate including an expansible chamber having a movable wall connected to said waste gate, spring means biasing said wall to a position wherein said waste gate is open, and means for supplying fluid under pressure to said chamber to move said waste gate toward closed position including a port in the wall of said cylinder, said port Ibeing normally closed by said piston but opening into the high pressure end of said cylinder when said throttle reaches its wide open position.

6. Control apparatus for an internal combustion engine having a conduit for combustion air ilowing to said engine, a pair of throttle blades for controlling the flow of air thru said conduit, a supercharger for supplying air under pressure to said engine, an exhaust gas turbine for. driving said supercharger, and a waste gate for regulating the operation of said supercharger; said control apparatus comprising means for manually moving one of said throttle blades, a first hydraulic servo-motor for operating the other blade including a, cylinder and a piston reciprocable therein, means for selectively supplying fluid at high pressure to either end of vsaid cylinder and connecting the opposite end ofsaid cylinder to a source of lower pressure to cause translation of said piston selectively in opposite directions, means responsive to the position of said one blade for operating said selective supply means, a second hydraulic servo-motor for operating; said waste gate including an expansible chamber having a movable wall connected to said waste gate, spring means biasing said Wall to a position wherein said waste gate is open, and means for supplying fluid under pressure to said chamber to move said waste gate toward closed position including a port in the wall of said cylinder, said port being normally closed by said piston but opening into the high pressure'end of said cylinder when said other blade reaches its wide open position.

7. Control apparatus for an internal combustion engine having a throttleA for controlling the flow of combustion air to said engine, a supercharger for supplying air under pressure to said engine, a driving connection between said engine and said supercharger, variable gear ratio transmission means in said connection, and means for shifting said transmission from low to high gear ratio; said control apparatus comprising a hydraulic servo-motor for operating said throttle, a valve for controlling said servo-motor, said valve having a neutral position in which said servomotor is stationary and being effective upon movement from said neutral position in one direction to cause operation of said throttle in an opening direction and upon movement in the opposite direction to cause operation of said throttle in a closing direction, a -hydraulic servo-motor for operating said shifting means including an eX- pansible chamber having a, movable Wall connected to said shifting means, spring means biasing said shifting means to its low supercharger speed position, and means for supplying fluid under pressure to said chamber to move said shifting means to its high supercharger speed position including a port adjacent said valve and normally closed thereby, but opened thereby upon movement of said valve in said one direction beyond its normal range of movement.

8. Control apparatus for an internal combustion engine havingA athrottle for controlling the iiow of combustion air to said engine, a supercharger for supplying air under pressure to said engine, a driving connection between said engine and said supercharger, variable gear ratio transmission means in said connection, and means for shifting said transmission from low to high gear ratio; said control apparatus comprising a hydraulic servo-motor for operating said throttle, a valve for controlling said servo-motor, said valve having a neutral position in which said servomotor is stationary and being effective upon movement from said neutral position in one direction to cause operation of said throttle in an opening direction and uponmovement in the opposite direction to cause operation of said throttle in a closing direction, a hydraulic servo-motor for operating said shifting means including an expansible chamber having a movable Wall connected to said shifting means, spring means biasing said vshifting means to its4 low supercharger speed position, means for supplying uid under pressure to said chamber to move said shifting means to its high supercharger speed position including a port adjacent said valve and normally closed thereby, but Opened thereby upon movement of said valve in said one direction beyond its normal range of movement, and time delay means for slowing the operation of said shifting means to its high supercharger speed position including a second expansible chamber connected to said first mentioned chamber, and resilient means associated with said second chamber to resist its expansion, said resilient means having a spring rate lower than that of said spring means so that said second chamber lls before said Wall starts to move.

9. Control apparatus for an internal combustion engine, comprising a conduit for air flowing to said engine, a pair of throttle blades for controlling the iiow of air thru said conduit, means for manually moving one of said throttle blades, motor means for moving the other of said throttle blades, a device for controlling said motor means, said device having a neutral position in which said motor means is stationary and being effective upon movement from said neutral position in either direction to cause operation of said motor means in a corresponding direction, an expansible chamber having a movable wall connectcd to said device so as to move said device in a throttle closing direction upon expansion of said chamber, means for controlling the pressure in said chamber including a restricted inlet passage, a restricted outlet passage, and pilot valve means responsive to the rate of combustion air flow to said engine for controlling said outlet passage so as to maintain the pressure in said chamber substantially proportional to the rate of air flow over most of the range of variation of said air iiow, rst spring means biasing said pilot valve means toward closed position and effective to establish a minimum pressure in said chamber, second spring means. acting on s aid movable wall in opposition to the pressure in said chamber, and means associated with said vone throttle blade for increasing the opposing force of said second spring means as said one blade is moved toward open position and for decreasing the oppOsing force of said second spring means as said one blade is moved toward closed position, said last-named means and said rst and second spring means cooperating to cause movement of said other blade to closed position wheneverA the force ofv said second spring means becomes less than that due to the minimum pressure in said chamber.

10. Control apparatusfor an internal combustion engine, comprising a conduit for air flowing to said engine, a pair of throttle blades for controlling the flow of air thru said conduit, means for manually moving one of said throttle blades, motor means for moving the other of said throttle blades, a device for controlling said motor means, said device having a neutral position in which said motor means does not operate in either direction and being eiective upon movement from said neutralposition in either direction to cause operation of said motor means in a corresponding direction, means responsive to the rate of air flow thru said conduit for moving said device in an air ow decreasing direction, spring means opposing said air flow responsive means, means associated with said one throttle blade 'for increasing the opposing force of said spring means as said one blade is moved toward open position and for decreasing the opposing force of said spring means as 12 said one blade is moved toward closed position, and means for positively closing said other blade under engine idling conditions so that the air flow is then controlled by said one blade only.

11. Control apparatus for an internal combustion engine having a conduit for combustion air flowing to said engine, a supercharger for supplying air under pressure to said engine, and means for varying the speed of said supercharger; said control apparatus comprising a pair of throttle blades for controlling the ow of air thru said conduit, means for manually moving one of said throttle blades, motor means for moving the other of said throttle blades, a device for controlling said motor means, said device having a neutral position in which said motor means is stationary and being effective upon movement from said neutral position in either direction to cause operation of said motor means in a corresponding direction, means responsive to the rate of air iiow thru said conduit for moving said device in an air ow decreasing direction, spring means opposing said air flow responsive means, means associated with said one throttle blade for increasing the opposing force of said spring means as said one blade is moved toward open position and for decreasing the opposing force of said spring means as said one blade is moved toward' closed position, and means for operating said speed varying means in a 'supercharger speed increasing sense upon failure of said air flow responsive means to balance the force of said spring means.

12. Control apparatus for an internal combustion engine having a throttle for controlling the flow of combustion air to said engine, a supercharger for supplying air under pressure to said engine, a driving connection between said engine and said supercharger, variable gear ratio transmission means in said connection, and means for shifting said transmission from low to high gear ratio; said control apparatus comprising a hydraulic servomotor for operating said throttle, a valve for controlling said servo-motor, said Valve having a neutral position in which said servo-motor is stationary and being eiective upon movement from said neutral position in one direction to cause operation of said throttle in an opening direction and upon movement in the opposite direction to cause operation of said throttle in a closing direction, a hydraulic servomotor for operating said shifting means including an expansible chamber having a movable wall connected to said shifting means, spring meansr biasing said shifting means to its low supercharger speed position, means for supplying uid under pressure to said chamber to move said shifting meansA to its high supercharger speed position including a port adjacent said valve and normally closed thereby, but opened thereby upon movement of said valve in said one direction beyond its normal range of movement, and means for draining uid from said chamber to cause said vspring means to operate said shifting means to its low supercharger speed position including aV second valve movable ooncurrently with said throttle and closed only when said throttle is in afrange of positions adjacent its Wide open position.

13. Control apparatus for an internal combustion engine having a throttle for controlling the flow of combustion air to said engine, a supercharger for supplying air underpr'essure to s aid engine, a driving connection between said engine and said supercharger, variablev gear ratio transmission means in said connection, and means for shifting said transmission from low to high gear ratio; said control apparatus comprising a hydraulic servo-motor for operating said throttle, a valve for controlling said servo-motor, said valve having a neutral position in Which said servo-motor is stationary and being eiective upon movement from said neutral position in one direction to cause operation of said throttle in an opening direction and upon movement in the opposite direction to cause operation of said throttle in a closing direction, a hydraulic servomotor for operating said shifting means including an expansible chamber having a movable Wall connected to said shifting means, spring means biasing said shifting means to its low supercharger speed position, means for supplying fluid under pressure to said chamber to move said shifting means to its high supercharger speed position, and means for draining uid from said chamber to cause said spring means to operate said shifting means to its low supercharger speed position including a second valve movable concurrently with said throttle and closed only when said throttle is in a range of l positions adjacent its Wide open position.

14. Control apparatus for an internal combustion engine having a throttle for controlling the iioW of combustion air to said engine, a supercharger for supplying air under pressure to said engine, a driving connection between said engine and said supercharger, variable gear ratio transmission means in said connection, and means for shifting said transmission fromv low to high gear ratio; said control apparatus comprising a hydraulic servo-motor for operating said throttle, a valve for controlling said servo-motor, said valve having a neutral position in which said servo-motor is stationary and being eiective upon movement from said neutral position in one direction to cause operation of said throttle in an opening direction and upon movement in the opposite direction to cause operation of said throttle in a closing direction, a hydraulic servomotor for operating said shifting means including an expansible chamber having a movable Wall connected to said shifting means, spring means biasing said shifting means to its low supercharger speed position, means for supplying fluid under pressure to said chamber to move said shifting means to its high supercharger speed position including a port adjacent said valve and normally closed thereby, but opened thereby upon movement of said valve in said one direction beyond its normal range of movement, and means for draining fluid from said chamber to cause said spring means to operate said shifting means to its low supercharger speed position.

l5. Fluid ow control apparatus, comprising a conduit `for said fluid, throttle valve means including a pair of adjacent valve members for controlling the iiow of uid thru said conduit, means for manually moving one of said members, motor means for moving the other of said members, and means connected for concurrent movement with said one member for controlling said motor means to coordinate the movements of said other member.

16. Fluid flow control apparatus comprising a conduit for said uid, a pair of throttle members for controlling the ow of fluid thru said conduit, means for manually moving one of said throttle members, motor means for moving the other of said throttle members, a device for controlling said motor means, said device having a neutral position in which said motor means is stationary and being eiective upon movement from said neutral position in either direction to cause operation of said motor means in a corresponding direction, means responsive to the rate of uid flow thru said conduit for moving said device in a flow decreasing direction, spring means opposing said flow responsive means, and means associated with said one throttle member for increasing the opposing force of said spring means as said one member is moved toward open position.

17. Fluid flow control apparatus comprising a conduit for said uid, a pair of throttle members for controlling the flow of uid thru said conduit, means for manually moving one of said throttle members, motor means for moving the other of said throttle members, means responsive to the rate of fluid flow thru said conduit for controlling said motor means to maintain `a substantially constant rate of flow, means for varying the setting of said iiow responsive means, and means associated with said one throttle member for operating said setting varying means in a ow increasing sense as said one member is moved toward open position.

LEIGHTON LEE, I1.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 941,426 Loudon Nov. 30, 1909 2,297,235 Mller Sept. 29, 1942 2,305,810 Mller Dec. 22, 1942 2,404,262 Whiteld July 16, 1946 2,423,417 Stokes et al. July 1, 1947 

